package com.javawork.juc.threadLocal;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * 【强制】必须回收自定义的ThreadLocal变量，尤其在线程池场景下，线程经常被复用，如果不清理自定义的ThreadLocal变量，可能会影响后续业务
 * 逻辑和造成内存泄露等问题。尽量在代理中使用try-finally块进行回收
 * @author zhangxiaolu
 * @since 2023-02-13 22:23
 */
public class ThreadLocalDemo2 {

    public static void main(String[] args) {
        MyData myData = new MyData();
        ExecutorService threadPool = Executors.newFixedThreadPool(5);
        try {
            for (int i = 0; i < 10; i++) {
                threadPool.submit(() -> {
                    try {
                        Integer beforeInt = myData.threadLocalField.get();
                        myData.add();
                        Integer afterInt = myData.threadLocalField.get();
                        System.out.println(Thread.currentThread().getName() + "\t beforeInt : " + beforeInt + "\t afterInt : " + afterInt);
                    } finally {
                        myData.threadLocalField.remove();
                    }
                });
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            threadPool.shutdown();
        }
    }
}

class MyData{
    ThreadLocal<Integer> threadLocalField = ThreadLocal.withInitial(() -> 0);

    public void add() {
        threadLocalField.set(1+threadLocalField.get());
    }
}